One of a kind. It's just a shame there is apparently still no singleplayer...
The original game was also really great, but the Source version is clearly the one to look at. Like the original, you choose either to be the US army or the Wehrmacht (just ordinary soldiers, not nazis) and pick different classes, each with their own special weapons, possessions and abilities. You find whatever server you can, then choose the side and class, jump into the action and fight to win. The difference here is that the Source engine provides far more advanced visual and animated presentation, but still does not appear too demanding at all. The brilliant music, sound effects are here and you cannot say they are weak and disappointing.
While the game is indeed fantastic fun and a perfectly engaging multiplayer experience, I could not help but feel that the lack of a singleplayer was disappointing. There is a chance I could have that once I purchase Garry's Mod, but at the moment I am feeling a wee bit let down. I really love multiplayer-based action, but at this stage, I thought Valve would think about adding a solo mode for single-player fans. I dislike it when the only way I can join the action is through an internet connection which applies to online-only games.
I am not saying that the game is far from a worthy package. I am just saying that I believe Valve should have included more than just a graphically updated version of a classic. Even if the AI was bad, I would still be able to tolerate it. That's not to say it is worse though, it is a much more valuable purchase than the original version and the cheap price it is today proves it cannot be missed. I just hope Valve will eventually release maybe a sequel which includes a campaign or solo mode as well.